Caller: Supposedly Telstra NBN

One of those scam calls from Telstra NBN, just NBN or Telstra. Supposedly from their security department to alert me that there is use of my broadband by unknown devices. They will then want you to download some software to my computer so that they can monitor your broadband useage or something. I strung them along once to see what they were angling for but never let them get that far. I imagine whatever you download onto you computer enables them to access your passwords etc to get access to various accounts to get your money or for identity theft or whatever. Blocked this number but I have had other such calls from a private number.